Question

In: Advanced Math

Use the formula for the sum of the first n terms of an arithmetic series to find the sum of the first eleven terms of the arithmetic series 2.5, 4, 5.5, … .

Use the formula for the sum of the first n terms of an arithmetic series to find the sum of the first eleven terms of the arithmetic series 2.5, 4, 5.5, … .

Solutions

Expert Solution

Consider the arithmetic sequence,

2.5, 5, 5.5, …

 

First term of the sequence is a1 = 2.5

 

Compute common difference as follows:

d = a2 – a1

    = 4 – 2.5

   = 1.5

 

Use the formula for nth term of an arithmetic sequence,

an = a1 + (n – 1)d ...... (1)

 

Substitute a1 = 2.5, d = 1.5 and n = 11 in formula (1) and compute 11th term of the sequence,

a11 = 2.5 + (11 – 1) × 1.5

       = 2.5 + 10 × 1.5

       = 2.5 + 15

       = 17.5

 

Use the formula for the sum of first n terms of an arithmetic sequence,

Sn = n(a1 + an)/2 ...... (2)

 

Substitute a1 = 2.5, an = 17.5 and n = 11 in formula (2) and simplify,

S11 = 11(2.5 + 17.5)/2

        = 11 × 20/2

        = 110


Related Solutions

Use the formula for the sum of the first n terms of a geometric series to find S9 for the series 12, 6, 3, 3/2 , …
Use the formula for the sum of the first n terms of a geometric series to find S9 for the series 12, 6, 3, 3/2 , …  
For the following exercises, use the formula for the sum of the first n terms of each arithmetic sequence. 3.2 + 3.4 + 3.6 + … + 5.6
For the following exercises, use the formula for the sum of the first n terms of each arithmetic sequence.3.2 + 3.4 + 3.6 + … + 5.6
For the following exercises, use the formula for the sum of the first n terms of each geometric sequence, and then state the indicated sum.
For the following exercises, use the formula for the sum of the first n terms of each geometric sequence, and then state the indicated sum.
If the sum of first 6 terms is 9 times to the sum of first 3 terms of the same G.P., then common ratio of the series will be
If the sum of first 6 terms is 9 times to the sum of first 3 terms of the same G.P., then common ratio of the series will be
Use a definition of power series, to find he first 5 terms of a Taylor series...
Use a definition of power series, to find he first 5 terms of a Taylor series of f(x) at a =9 for f(x)=root of x
Find the sum (n=5, to infinity) of the series (n2 -n)/2n
Find the sum (n=5, to infinity) of the series (n2 -n)/2n
use the definition of the Taylor series to find the first four nonzero terms of the...
use the definition of the Taylor series to find the first four nonzero terms of the series for f(x) centered at x = a a) f(x) = xe^x, a = 0 b) f(x) = sin (x), a = π/6
5. Find the sum of terms in given arithmetic sequence 1 + 3 + 5 +...
5. Find the sum of terms in given arithmetic sequence 1 + 3 + 5 + ... + 59 6. Find the sum of terms in given arithmetic sequence 2 + 5 + 8 + ... + 41 7.Given a geometric sequence 6 + 2 + 2/3 + ... is this sequence converging or diverging, if it is converging find it's sum
Determine the formula for the calculation of sum of n terms in a geometric progression (G.P)?
Determine the formula for the calculation of sum of n terms in a geometric progression (G.P)?  
Use the definition of Taylor series to find the first three nonzero terms of the Taylor...
Use the definition of Taylor series to find the first three nonzero terms of the Taylor series (centered at c) for the function f. f(x) = 7 tan x,  c = 9π
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT